Do you have the hitch yet? Most of the better hitches come with and isolator that connects the trailer to the bike and isolates the electronics of the trailer from the delicate electronics of the Goldwing. Plug and play.
There is no difference in wiring a trailer to an ABS model or a non-ABS model. ABS affects only the function of the brakes and has nothing to do with the brake/turn/tail lights. An isolation harness is a good idea to keep the trailer wiring separate from the bike electronics but even that isn't absolutely necessary.